A 10 to 40 GHz Stacked Push-pull Class-B Power Amplifier in 45-nm CMOS SOI with 20.4 dBm PSAT and Continuously Supporting 72 Gb/s 64-QAM and 10 Gb/s 1024-QAM Signals

This paper presents a broadband, high-efficiency stacked push-pull class-B power amplifier in 45-nm CMOS SOI that has a peak PSAT of 20.4dBm and a maximum power-added efficiency of 40.2%. Harmonic superposition of the drain-source current waveforms in a push-pull topology is utilized to enhance bandwidth(BW) and linearity while maintaining the same efficiency level as a regular Class-B PA. Equivalent circuits of tapered transmission lines, along with a low quality-factor inductive-resistive matching are used for broadband input and output matching of the PA. The PA achieves a very flat Psat with a record 1-dB BW of 30 GHz(120%) over 10 to 40GHz. The PA has a peak small-signal gain of 13.8 dB with a 3-dB BW from 11.5 to 44.9GHz. Furthermore, based on modulation tests, the proposed PA supports 10 Gb/s 1024-QAM and 6–72 Gb/s 64-QAM modulated signals. The DC power consumption is 182mW,and the chip dimensions are 0.92mm×2.1 mm.